Water seal for pumps



Jan. 13, 1942. w. HOGAN 2,270,054

WATER SEAL FOR PUMPS Filed oct. 13. 1939 Patented Jan.. 13, 1942 WATERSEAL FOB PUMPS William Hogan, Augusta, Ga., aloignor to Georgia IronWorks, Augusta, Ga., a corporation of Georgia Application October 13,1939, Serial No. 299,383

2 Claims.

This invention relates to the art of fluid pumps and particularly tocentrifugal pumps designed for handling liquids or liquids containing orconveying solids.

Although not restricted thereto, the invention finds an improved eld ofuse in sand pumps for dredging operations and the like. In centrifugalpumps employed for such operations considerable diliiculty isencountered in maintaining a proper seal in order to preventrecirculation of material in the pump. Such recirculation materiallylowers the eiiiclency of the pump.

An object of this inventionA is to provide an improved seal forpreventing recirculation in centrifugal pumps and the like. l

Another object isv to provide' an improved construction of liquid sealbetween the impeller of a centrifugal pump and its adjacent face plates.

A further object is to provide in a centrifugal pump, a novelconstruction of seal ring and manner of mounting the same.

Other objects will be readily apparent to those skilled in the art.While the present disclosure constitutes a preferred embodiment by whichthe invention is reduced to practice, itis to be understood that withinthe scope of the invention as claimed any desired variations and changesmay be made in the structural details.

In the accompanying drawing, wherein like characters designate likeparts throughout the several Views:

Figure l is a central vertical section through the centrifugal pumpequipped with a seal in accordance with the invention.

Figure 2 is an enlarged fragmentary section illustrating the sealmounting detail oi Figure l.

Figure 3 is a fragmentary perspective of an inner seal ring employed inthe pump.

Figure 4 is a fragmentary perspective view of an outer seal ring, alsoused. A

Figure 5 is a central vertical section through a pump and illustratingthe disposition of sealing means on both the suction side and the hubside of the pump.

In detail the pump comprises a volute shell 6 within which is disposedan impeller 1 mounted on the end of the pump shaft 8 which has a bearingin the hub side plate 9; The suction side of the pump casing is closedin the usual manner by the suction side face plate III which iscentrally apertured to provide the suction inlet II for the pump, theinlet being co-axial with the pump shaft.

On its suction side the impeller 1 has rigidly visis secured thereto, asby bolts I2 or by welding, a peripherally stepped annular plate I3 whichrotates with the impeller within the annular chamber Il formed in thesuction side face plate I0.

Approximately in axial alignment with the outer step I5 of the runnerplate I3, the suction face plate III is formed with an undercut annulargroove I8 which receives the base flange of a rubber sealing ring I1.The ring I1 has a snap action in its engagement with the seating grooveI6 and it is securely retained in position by means-.of a metal lockring I8. The lock ring I8 is snapped in place inside the rubber ring andseats upon the ledge formed vby the outer wall oi the groove I8. Theouter peripheral face of the ring is tapered with respect to the sealring I1, so that when the ring 'I8 is snapped in place the base of thesealing ring is wedged radially into the seating groove I6 and is thusrmly anchored in position on the hub side face plate III. The rubbersealing ring I1 extends inwardly over the periphery of the outer step I5on the runner plate and has an internal bead I9 which bears against theperiphery of the step under the tension imparted by the resiliency ofthe ring.

The inner step 20 of the runner plate I3 is 'chamfered as at 2l alongits outer peripheral the ring bears against the cylindrical peripheryofthe step 2li, and the ring is anchored at its base by a retaining ring24 which is reversely tapered with respect to the periphery of the baseof theseal ring and which is snapped over the base of the seal ring towedge the same firmly into the undercut groove 23. It will be apparentthat by means of the snap rings I8 and 24 the outer seal ring and theinner seal ring are both rmly secured in position upon the suction sideof the face plate of the pump and they are assembled on this platebefore it is applied in position. This construction eliminates thenecessity for the use of headed or screw threaded fastening elements asa means of anchoring the sealing rings in place.

While the outer and inner steps I5 and 20, respectively, are shown asbing provided by the plate I3 which is attached to the impeller,

these steps may be cast as integral portions of the impeller, Yifdesired.

Figure 5 illustrates the construction of sealing ring assembly which isdisposed both at the suction side and at the hub side of the pump. Inorder to prevent unnecessary repetition, and in view of the fact thatdetails of sealing rings and retaining rings are identical at each sideof the pump, the same reference characters have been employed toindicate identical parts at each side, the only difference being that atthe respective sides of the pump the elements are reversed in position.I

The wall of the face plate I0 is provided with an aperture through whichwater or other liquid is supplied under pressure to the sealing chamberi4. The pressure at which the sealing medium is supplied to the chamberI4 is held at a higher point than the pressure existing within the pump.This results in a slight lifting of the outer seal ring bead IS whichpermits the sealing liquid, generally Water, to flow beneath the beadand lubricate its bearing on the step I5. The inner seal ring 22 isprovided with an annular series of bleeder passages 26 through which thesealing liquid from the chamber Il is permitted to pass in small volumeso that it becomes effective 1n lubricating the bearing between the ring22 and the step 20 of the runner plate.

As in all such pumps, a definite clearance space 21 exists between theimpeller 1 and the suction side face plate I0. A similar clearance space28 exists between the impeller and the hub side face plate 9. As thereis a high pressure in the volute 6 and a relatively lower pressure atthe inlet Il, at which a definite suction exists,

there is a constant tendency for the material which the pump is handlingto be forced back from the volute through the clearances 21 and 28 tothe axial area of the impeller and thus to be recirculated with theconsequent lowering of pump efnciency. In the present invention thehigher pressure maintained within the chamber Il insures againstcollapse of the outer sealing ring l1 so that this ring effectivelyblocks off any passage of pump material radially inward along thepassage between the impeller and the adjace'nt base plate. At the sametime the chamber pressure maintains the ring 22 in sealing contact withthe runner step 20 and only a small l tween the runner plate and theside portion of the sealing liquid is allowed to pass through thebleeder passages 2B. This small volume of the sealing liquid isadequate'to maintain lubrication. The chamfered portion 2i oi' the step2li of the runner plate I3 eliminates'any possibility of the ring22.becoming pinched beface of the pump shell.

-An important feature of the invention resides ln the fact that thecontacting faces of the outer sealing ring I1 and its retaining ring I8are reversely tapered as are also the contacting faces of the innersealing ring 22 and its retaining ring 24. `'I'his tapering results in adefinite wedging action which crowds the base of each ring radially intoits undercut holding groove. No projecting parts are exposed and theentire Aassembly is of simple rugged construction.

I claim:

1. In a centrifugal pump, a face plate having an axial recess open tothe inner side thereof, an undercut annular groove in a wall of therecess, a rubber sealing ring having a base flange seated in the groove,a resilient retaining ring overlying and in pressure engagement with thesealing ring in radial alignment with its base flange. and thecontacting face of the retaining ring being beveled inwardly toward thesealing ring from the outer to the inner side faces of the retainingring whereby to Wedge the base flange of the sealing ring radially intoits groove, said resilient retaining ring constituting the sole meansfor holding said sealing ring in place.

2. In a centrifugal pump, a face plate having an axial recess opening tothe inner side thereof, an undercut annular groove in a wall of therecess, a rubber sealing ring having a base flange seated in the groove,said ring having its surface opposite to the base flange beveled fromthe base of the ring away from the opposite flange bearing side of thering, a resilient retaining ring overlying and in pressure engagementwith the sealing ring in radial alignment with its base flange, and thecontacting face of the retaining ring being reversely beveled withrespect to the surface of the sealing ring whereby to wedge the baseflange of the sealing ring radially into its groove, said resilientretaining ring constituting the sole means for holding said sealing ringin place.

WILLIAM HOGAN.

